I am new to ReactJs. My Project is fetching data from my backend, which contains a Cell Id, and then sending that Cell Id to another api and receiving the latitude and longitude of the Cell ID. In order to do this I have to store the locations for each cell Id. It seems that I am able to store the latitude and longitude in this.state.loc. However I am running into an issue when mapping through that array to put markers on the map. In the first code block when I try to log the latitude of the locations to the console it only logs one of them.
import React, {Component,useState, useEffect} from 'react';
import './App.css';
import {GoogleMap, withScriptjs, withGoogleMap, Marker, useLoadScript, InfoWindow} from "react-google-maps";
class App extends Component {
constructor(props) {
super(props);
this.state = {
users: [],
loc:[{}]
};
}
componentDidMount() {
fetch('/users')
.then(res=>res.json())
.then(users=>this.setState({users}))
.then(users=>this.state.users.map(user => {
var num = user.CallingCellID
if(num != null) {
var digits = (num).toString().split('');
var realDigits = digits.map(Number);
var mcc = 419;
var mnc = 4;
var lac = (realDigits[6]*1000) + (realDigits[7]*100) + (realDigits[8]*10) + (realDigits[9]*1);
var cid = (realDigits[10]*10000)+ (realDigits[11]*1000) + (realDigits[12]*100) + (realDigits[13]*10) + (realDigits[14]*1);
fetch("https://api.mylnikov.org/geolocation/cell?v=1.1&data=open&mcc=419&mnc=4&lac="+lac+"&cellid="+cid)
.then(response => response.json())
.then(result=> {
const locations = result.data;
if(locations.lat != undefined) {
var x = [{lat: locations.lat, lng: locations.lon}];
Promise.all(x).then(data => {this.setState({ loc: data })})
}
});
}
}));
}
render() {
const MyMapComponent = withScriptjs(withGoogleMap((Map) =>
<GoogleMap defaultZoom={2} defaultCenter={{ lat: -34.397, lng: 150.644 }}>
{this.state.loc.map(l=>console.log(l.lat))}
</GoogleMap>))
return (
<div className="App">
<header className="App-header">
<form>
<label for="Location Search"> Location Search: </label>
<input type = "text" id = "Location Search" name = "Location Search"/>
<label for="Account Search"> Account Search: </label>
<input type = "text" id = "Account Search" name = "Account Search"/>
<label for="IMSI Search"> IMSI Search: </label>
<select id="IMSI Search" name="IMSI">
<option value="1">1</option>)
</select>
<label for="IMSI RANGE:"> IMSI RANGE </label>
<input type = "text" id = "IMSI RANGE" name = "IMSI RANGE"/>
<input type = "text" id = "IMSI RANGE2" name = "IMSI RANGE2"/>
</form>
<div id = "googlemap">
<MyMapComponent
isMarkerShown
googleMapURL="https://maps.googleapis.com/maps/api/js?key=AIzaSyCa3cfZfuFgpKPUWpXZv7WejZ7u_093A3s"
loadingElement={<div style={{ height: `800px` }} />}
containerElement={<div style={{ height: `1500px` }} />}
mapElement={<div style={{ height: `800px` }} />}
/>
</div>
</header>
</div>
);
}
}
export default App;
But in the code block below, when I move the map function for loc outside myMapComponent, and just below render(), it successfully logs the latitudes to the console.
render() {
{this.state.loc.map(l=>console.log(l.lat))}
const MyMapComponent = withScriptjs(withGoogleMap((Map) =>
<GoogleMap defaultZoom={2} defaultCenter={{ lat: -34.397, lng: 150.644 }}>
</GoogleMap>))
I am new to react, so I am not sure what is the issue. Im not sure if it has to do with the way I stored the locations for each Cell ID, or if it's some other issue.
You will have to use a callback function because after calling
setState , the data might not be updated immediately for use.
You will need to pass a callback function like this
this.setState({users}, () => {
**Do your this.state.users.map **
})
You can refer to this post also.